Michigan jurors, after 11 hours of deliberations, found Jennifer Crumbley guilty of involuntary manslaughter on Tuesday for the gun rampage committed by her son, who carried out the state’s deadliest school shooting more than two years ago.
Ms. Crumbley, 45, was convicted on four counts of involuntary manslaughter, one for each of the four students who were shot to death by her son at Oxford High School on Nov. 30, 2021. The son, Ethan Crumbley, who was 15 at the time, used a pistol to kill Madisyn Baldwin, 17; Tate Myre, 16; Justin Shilling, 17; and Hana St. Juliana, 14. Seven other people were injured. The gun was a gift from his parents.
She faces a maximum penalty of 15 years in prison after being convicted of all four counts.
Ethan, who pleaded guilty to 24 charges including first-degree murder, was sentenced last year to life in prison without the possibility of parole. He did not testify in his mother’s trial. Ms. Crumbley’s husband, James Crumbley, 47, will be tried separately in March.
The trial became a lightning rod for issues of parental responsibility at a time of frequent cases of gun violence carried out by teenagers and children.
In the last few months, parents whose children carried out gun violence in other states have pleaded guilty to charges of reckless conduct or neglect, part of a push by some prosecutors to hold parents accountable when they are suspected of enabling deadly violence.
But the charges against Ms. Crumbley were even more serious, making her trial a significant test case for prosecutors.
At the courtroom in Pontiac, Mich., jurors spent seven days listening to wrenching testimony from nearly two dozen witnesses, including Ms. Crumbley, who testified in her own defense for about three hours last week.
The prosecutors argued that Ms. Crumbley should have noticed her son’s distress and stopped him from committing an act of unspeakable violence. Marc Keast, one of the prosecutors, said that she and her husband “didn’t do any number of tragically small and easy things that would have prevented all of this from happening.”
But the defense lawyer, Shannon Smith, depicted Ms. Crumbley as a “hypervigilant mother” who was attentive to her son’s needs and could not have foreseen what would happen.
Ms. Smith also argued that parenting could be a messy and unpredictable job, and that no mother could be perfect. “This case is a very dangerous one for parents out there,” she said during her closing arguments on Friday.
During the trial, the prosecutors focused in part on Ethan’s access to a firearm. But jurors also had to wrestle with a more abstract question: whether witness testimony — along with an extensive collection of text messages — could be a reliable window into a troubled teenager’s state of mind or a mother’s relationship with her son.
Jurors were shown messages that Ethan sent to a friend in April 2021, complaining of insomnia, paranoia and hearing voices. The jurors were also shown messages that he sent to his mother in March 2021, in which he suggested that their home was haunted by a demon. Ms. Crumbley, prosecutors pointed out, did not always respond.
But in her testimony, Ms. Crumbley said that Ethan and his parents had joked for years about whether their house was haunted, adding that her son was just “messing around.”
Prosecutors also shared messages exchanged between Ms. Crumbley and her husband, colleagues and friends, which they said suggested that Ms. Crumbley had paid more attention to her two horses, and her extramarital affair, than to her son’s needs.
Ms. Crumbley testified that she had not seen her son as a danger to others. “As a parent, you spend your whole life trying to protect your child from other dangers,” she said. “You never would think you have to protect your child from harming somebody else.”
While Ms. Crumbley accompanied Ethan to a shooting range a few days before the rampage, she testified on Thursday that her husband, who had purchased the gun used in the shooting, was more familiar with firearms and had been responsible for storing the Sig Sauer pistol.
Ms. Crumbley also described a meeting with school officials that took place about two hours before the attack. She and her husband had been called to the high school after Ethan wrote troubling things on a math worksheet, including the phrase “blood everywhere.”
Ms. Crumbley said that after a counselor shared his concerns about Ethan’s mental health, they decided together that her son could stay at school rather than go home alone. They did not search his backpack, which contained the pistol that he would soon turn on his schoolmates.
On Thursday, a detective guided jurors through the pages of Ethan’s journal, which was found at the school after the shooting. The teenager had written about a plan to cause bloodshed, adding drawings of guns and pleas for help regarding his mental health.
“My parents won’t listen to me about help or a therapist,” Ethan wrote. But Ms. Crumbley said that she had never seen the journal entries, nor heard her son ask for a therapist.
Prosecutors had also suggested that the Crumbleys tried to flee the authorities by leaving their home in Oxford shortly after the shooting. The couple was arrested in Detroit on Dec. 4, 2021. Ms. Smith, the defense lawyer, argued that they feared for their safety in the face of relentless threats, and Ms. Crumbley testified that she had planned to turn herself in.
Campbell Robertson contributed reporting.